Following up on the successful development of a multicapillary model for the estimation of regional myocardial flows by NMR using an intravascular contrast agent, we will develop the techniques for estimating regional myocardial blood flows using a larger class of markers, namely those which escape from the blood during transcapillary passage. The first stage requires the recorded data on the form of the input function; in later stages we will try to estimate the input function form so that the analysis will be suitable for organs like the brain where the input is not readily recorded directly. The method development includes sensitivity analysis, assessment of ranges of applicability, susceptibility to noise, and dependence upon data acquisition rates. this project is the direct successor to D.II.E.1.